For the first time, scientists determined the biodiversity of tiny creatures called arthropods in the average United States home.

Published in the journal PeerJ, the new study estimates Americans live with anywhere from 100 to 211 different species of the tiny invertebrates.

"I was surprised by the number of specimens we collected from very typical homes, as well as how many rooms we found them in," study lead author Matt Bertone, an entomologist at North Carolina State University, told Discovery News. "For instance I didn't expect some groups to be in every home we sampled, and I would not have expected, for example, cobweb spiders to be found in 65 percent of rooms.

"A variety of ants (Formicidae) can commonly be found in homes. These social insects often form trails of workers looking for food and water."

For their study, the researchers 50 houses in or near Raleigh, N.C. between May and Oct. of 2012, searching for any and all arthropods in any state.

"This was exploratory work to help us get an understanding of which arthropods are found in our homes," Bertone said in a press release. "Nobody had done an exhaustive inventory like this one, and we found that our homes host far more biodiversity than most people would expect.

"While we collected a remarkable diversity of these creatures, we don't want people to get the impression that all of these species are actually living in everyone's homes.

"Many of the arthropods we found had clearly wandered in from outdoors, been brought in on cut flowers or were otherwise accidentally introduced. Because they're not equipped to live in our homes, they usually die pretty quickly."